The air intake manifold of a multi-cylinder engine is a branched pipe arrangement which connects the valve ports of each cylinder with the air inlet. In a carbureted engine, it would be connected between the valve ports and the carburetor, which would be downstream of the air inlet. The manifold can have considerable effect on engine performance. The intermittent or pulsating nature of the air flow through the manifold into each cylinder may develop resonances (similar to the vibrations in organ pipes) in the air flow at certain speeds. These may increase the volumetric efficiency and thus the power at certain engine speeds, but may reduce such efficiency at other speeds, depending on manifold dimensions and shape. Therefore, each manifold passageway is ideally tuned to a length calculated to maximize or minimize a chosen criteria, such as sound or efficiency.
Conventional manifolds can usually be broken into three distinct parts, the plenum, the runners (fluid conduits or pipes), and an attachment portion having an engine-attaching surface. For conventional plastic manifolds, there are two processes currently accepted as production methods, the fusible core process and the multi-shell, welded process. The fusible core process is capital intensive and difficult to keep in operation. The multi-shell welded manifold process produces relatively large parts which waste significant underhood room. With ever-decreasing available underhood packaging room, the problem of fitting a manifold to an engine becomes a greater challenge.
Accordingly, it is desirable in the art of engine manifolds to provide a tuned manifold which has smaller packaging requirements and which is easy to manufacture.
The present invention incorporates the function of a plenum, attachment flange, and tuned runners into a simply molded box with interior walls in order to save significant cost and underhood room.
The present invention also provides a manifold system which is easier to manufacture than many currently used manifolds.
The present invention further provides a manifold assembly which has smaller packaging requirements and which is simple in structure, easy to mass produce, durable in use, and refined in appearance.
The present invention provides an air intake manifold for use with an internal combustion engine having a labyrinth runner configuration in order to reduce the amount of space consumed by the manifold. The manifold is preferably made from a plastic material for reducing the weight of the manifold and for providing fabrication by an inexpensive and relatively simple molding process.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood however that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. For example, while the manifold of the present invention is extremely useful for use as an intake manifold for an internal combustion engine, it may find utility as a manifold for use with compressors, pumps and other apparatus.